Mercurial > hg > octave-terminal
changeset 7633:ba15376ddfe1
Add the contrast function
author | David Bateman <dbateman@free.fr> |
---|---|
date | Tue, 25 Mar 2008 12:03:26 -0400 |
parents | d6e63a15cc75 |
children | ae90e05ad299 |
files | scripts/ChangeLog scripts/image/Makefile.in scripts/image/contrast.m |
diffstat | 3 files changed, 58 insertions(+), 4 deletions(-) [+] |
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--- a/scripts/ChangeLog +++ b/scripts/ChangeLog @@ -1,3 +1,7 @@ +2008-03-25 David Bateman <dbateman@free.fr> + + * image/contrast.m: New function. + 2008-03-24 Thomas Weber <thomas.weber.mail@gmail.com> * pkg/pkg.m: Allow installation of already extracted packages.
--- a/scripts/image/Makefile.in +++ b/scripts/image/Makefile.in @@ -34,10 +34,10 @@ INSTALL_DATA = @INSTALL_DATA@ SOURCES = __img__.m __img_via_file__.m autumn.m bone.m brighten.m colormap.m \ - cool.m copper.m flag.m gmap40.m gray.m gray2ind.m hot.m hsv.m hsv2rgb.m \ - image.m image_viewer.m imagesc.m imshow.m ind2gray.m ind2rgb.m jet.m \ - loadimage.m ntsc2rgb.m ocean.m pink.m prism.m rainbow.m rgb2hsv.m rgb2ind.m \ - rgb2ntsc.m saveimage.m spring.m summer.m white.m winter.m + contrast.m cool.m copper.m flag.m gmap40.m gray.m gray2ind.m hot.m hsv.m \ + hsv2rgb.m image.m image_viewer.m imagesc.m imshow.m ind2gray.m ind2rgb.m \ + jet.m loadimage.m ntsc2rgb.m ocean.m pink.m prism.m rainbow.m rgb2hsv.m \ + rgb2ind.m rgb2ntsc.m saveimage.m spring.m summer.m white.m winter.m IMAGES = default.img
new file mode 100644 --- /dev/null +++ b/scripts/image/contrast.m @@ -0,0 +1,50 @@ +## Copyright (C) 2008 David Bateman +## +## This file is part of Octave. +## +## Octave is free software; you can redistribute it and/or modify it +## under the terms of the GNU General Public License as published by +## the Free Software Foundation; either version 3 of the License, or (at +## your option) any later version. +## +## Octave is distributed in the hope that it will be useful, but +## WITHOUT ANY WARRANTY; without even the implied warranty of +## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +## General Public License for more details. +## +## You should have received a copy of the GNU General Public License +## along with Octave; see the file COPYING. If not, see +## <http://www.gnu.org/licenses/>. + +## -*- texinfo -*- +## @deftypefn {Function File} {} contrast (@var{x}, @var{n}) +## Return a gray colormap that maximizes the contrast in an image. The +## returned colormap will have @var{n} rows. If @var{n} is not defined +## then the size of the current colormap is used instead. +## @seealso{colormap} +## @end deftypefn + +function map = contrast (x, n) + + if (nargin == 1) + n = rows (colormap); + elseif (nargin == 2) + if (! isscalar (n)) + error ("contrast: n must be a scalar"); + endif + else + print_usage (); + endif + + x = x(:); + minx = min (x); + map = find (diff (sort ([round(n * ((x - minx) ./ (max(x) - minx))); [0:n]']))); + minm = min (map); + map = (map - minm) ./ (max (map) - minm); + map = [map, map, map]; +endfunction + +%!assert (contrast(1:100,10),[([0:9]/9)',([0:9]/9)',([0:9]/9)'],1e-10) +%!demo +%! image (reshape (1:100, 10, 10)) +%! colormap (contrast (1:100,10))